Sand cores as used for molding metal products are placed in casting cavities and openings to form passageways or hollow portions in the casting. Such cores are formed by combining sand and a binder substance, such as synthetic resins, in a core making machine having patterns or dies to shape the core. During the formation of such cores, small, fin-like extensions, known as "fins" or "flash" often develop along the junction between the core-making dies. These undesired fins must be removed or at least substantially reduced to such an extent that they do not impair the formation of the finished metal product during the casting process.
Until recently, removal of the undesired fins has been accomplished manually. That is, one would normally pick up a newly formed core and scrape the fins with a wire brush or a small rigid tool, such as a file or knife, to knock the fins off. This is not only time-consuming and costly, but the manual core handling often leads to the eventual destruction of a small percentage of cores due to dropping, too vigorous handling, or cracks induced during the fin knock-off procedure.
In a co-pending application Ser. No. 893,203, filed Apr. 4, 1978. of G. T. Dupre and T. M. DeMarco, entitled "Apparatus for Cleaning Sand Cores" and assigned to the same assignee herein, there is described a new and unique system for removing fins from sand cores by utilizing a falling curtain of metal shot or metal grit and including means for separating the cleaning material from the loosened sand to permit reuse of these particles. The system described therein includes a conveyor for transporting the sand cores during cleaning, means for delivering a falling curtain of metal shot or grit onto the moving sand cores to remove the undesired fins, and means at the end of the core conveyor for separating the shot or grit from the sand resulting from removal of the fins and for transferring the separated shot or grit to the delivery means above the core conveyor for reuse. While this unique core cleaning system operates entirely satisfactorily, it is now desired to provide an improved, more efficient core cleaning system of smaller size, with fewer components, and of less overall manufacturing cost. In particular, it is also desired to improve the shot or grit delivery apparatus of the prior system.